Certain early symptoms of Parkinson's include rigidity that can interfere with a patient's ability to write or sketch.

A test that involves drawing a spiral on a sheet of paper could be used to diagnose people at risk of developing Parkinson's disease, Australian researchers have found.

Parkinson's disease is a neuro-degenerative disorder that causes shaking, muscle rigidity and difficulty with walking.

Certain symptoms that appear early in Parkinson's, such as rigidity, can interfere with a patient's ability to write or sketch, thus contributing to the diagnosis of the disease.

The researchers developed specialised automated electronic system that measured writing speeds, pen pressures and produced the Composite Index of Speed and Pen-pressure (CISP) score in Parkinson's patients -- all three measurements clearly indicated whether a participant had Parkinson's or not.

"Our aim was to develop an affordable and automated electronic system for early-stage diagnosis of Parkinson's disease, which could be used easily by a community doctor or nursing staff," said Poonam Zham, from RMIT University in Melbourne.

In the study, published in the journal Frontiers in Neurology, the team used the system to measure pen speed and pressure during a simple spiral sketching task in a sample of healthy volunteers and Parkinson's patients with different levels of disease severity.

While pen speed and pressure alone were not sufficient to measure the severity between patients with different levels of Parkinson's, the new system with CISP score could tell whether the patients had level 1 or level 3 Parkinson's.

"The system can automatically provide accurate Parkinson's diagnosis and could also be used by community doctors to monitor the effect of treatment on the disease," Zham said.

"This simple device can be used by community doctors for routine screening of their patients every few years after the patients are above middle-age."